Electronic devices have proliferated in recent decades as a result of the phenomenal increase in capability and simultaneous reduction in their costs. These electronic devices generally all include transistors that are arranged and connected together in particular configurations to perform certain functions. In one example, transistors can be coupled together to perform amplifier functions to amplify audio signals for output to headphones. In another example, transistors can also be coupled together to perform logic functions, such as addition and multiplication, in microprocessors. In a further example, transistors can further be coupled together to store data, such as in memory and solid state storage (SSD) devices. It is no surprise, thus, that individual electronic components inside electronic devices can include tens, hundreds, thousands, or even millions of transistors to accomplish all of the functionality incorporated in the electronic devices.
One common configuration for transistors within various electronic components is to couple the drains of two transistors together. Transistors generally include at least three terminals for connections: a source, a drain, and a gate. A signal applied to the gate terminal can change a resistance between the source and drain terminals and cause current to flow through the transistor. Amplifier circuitry may include one or more pairs of transistors with the drain terminals connected together. One example of a semiconductor structure for two transistors with coupled drain terminals is shown in FIG. 1. FIG. 1 is an example cross-section illustrating two transistors coupled at their respective drain terminals. Two independent transistors 110 and 120 are manufactured in a substrate 102. The transistors 110 and 120 may include an n-well 112, in which resides a source 114 and a drain 116, and a gate terminal 118. The gate terminals 118 may be coupled together by wiring in other layers built above the transistors 110 and 120. The semiconductor structure of FIG. 1 illustrates the results of a conventional manufacturing process that takes a common template for a transistor and manufactures the templated transistor many times to form an electronic component. That is, if two transistors are needed in a circuit, then two transistors are manufactured and coupled together, such as through coupling 130, to perform the desired function.
The structure of FIG. 1 may be simple to manufacture by simply manufacturing two conventional structures in a substrate and connecting them in a particular manner. However, this structure consumes a large amount of space on the substrate. There are continuing demands on electronic components to be smaller, and also cheaper. This large structure, which is duplicated many, even hundreds of times, in an electronic device, may inhibit further reduction in sizes and cost of the devices.
Shortcomings mentioned here are only representative and are included simply to highlight that a need exists for improved electrical components, particularly for transistors employed in consumer-level devices, such as mobile phones. Embodiments described herein address certain shortcomings but not necessarily each and every one described here or known in the art.